Hydraulic transmission



June 17, 1941. c. L. McGAVERN 2246;450

HYDRAULIC TRANSMISSION Filed June 6, 1940 3 Sheets-Sheet 1 L,lv InventorQ L L r M) MAME: ZL/Vf- GA VERN, 3 I

A iiorney June 17, 1941. c, MCGAVERN 2,246,450 syn ammo TRANSMISSIONFiled June 6, 1940 3 Sheets-Sheet 2 Attorney June 17, 1941. c 1..MQGAQERN 2,246,450

-,HYDRAULIG "TRANSMISSION Filed June 6, 1940 3 Sheet-Sheet 3 $49.6CHARLES .L. M 64 l/m/v,

A iiorney Invenior Patented. June 17, 1941 UNITED STATES PATENT OFFICEHYDRAULIC TRANSMISSION Charles L. McGavern, Olean, N..Y Application June6, 1940, Serial No. 339,182

4 Claims.

The present invention relates to new and useful improvements inhydraulic transmissions particularly for motor vehicles although it willbe understood, of course, that a transmission constructed in accordancewith the present invention may be used for any other purpose for whichit may be found adapted and desirable.

The primary object of the invention is to provide, in a manner ashereinafter set forth, a hydraulic transmission embodying a novelconstruction, combination and arrangement wherein the speed ratio of thedriven member to the driving member may be manually controlled orautomatically controlled by the load on the former.

Other objects of the invention are to provide a hydraulic transmissionof the character de- B of suitable metal. Bolted at I on the forward endof the driven member 6 is, a. case'which is designated generally by thereference numeral I,

said case being rotatable and longitudinally movable in the cylindricalportion 3 of theflywheel 2. The case 8 includes metallic front and reardisks 9 and ill, respectively, which are suitably secured togethe as atll.- Projecting forwardly from. the disk 9 is a dome l2 providing afluid chamber I3. The forward end of the member 8 has formed therein aconcavity providing a fluid scribed which will 'be comparatively simplein construction, strong, durable, highly eiflcient and reliable in use,compact, light in weight and which may be manufactured and installed atlow cost.

All of the foregoing and still further objects and advantages of theinvention will become apparent from a study of the followingspecification, taken in connection withthe accompany.

ing drawingswherein like characters of reference designate correspondingparts throughout the several views, and wherein: p

Figure l is a view in side elevation of a hydraulic transmissionconstructed in accordance with the present invention.

Figure 2 is a cross sectional view, taken substantially on the line 2-2of Fig. 1.

Figure 3 is a View in longitudinal section through the transmission.

Figure 4 is a cross sectional view, taken substantially on the line 4-4of Fig. 3.

Figure *5 is a cross sectional view, taken substantially on the line 5-5of Fig. 3.

Figure 6 is a cross sectional view, taken substantially on the line 6-6of Fig. 3.

Figure 7 is a detail view in horizontal section,

- taken substantially on the line 1-1 of Fig. 4.

. Referring now to the drawings in detail, it will be seen that theembodiment of the invention which has been illustrated comprises a driveshaft l which is actuated by the engine (not shown) of the vehicle.Fixed on one end portion of the drive shaft l is a flywheel 2. Theflywheel 2 includes a cylindrical open end portion 3. Within theflywheel 2, adjacent the cylinder 3, isan annular, internally toothedgear 4. The forward end portion of the flywheel 2 j is journaled in asuitable bearing 5.

Mounted in alignment with the flywheel 2 is a rotary and longitudinallymovable driven member the coil spring 31. The driven member 6 has formedlongitudinally 8 into the flywheel 2 and haveflxed thereonpinion gearsI9 which are engaged with the gear 4 for actuation thereby. Ports 20establish communication between the chamber H and the chambers IS on oneside of the gear pumps I'l. Ports 2| establish communication between thefluid chamber I3 and the chambers IS on the other side of the ear pumpsll.

Mounted for longitudinal sliding movement in the domel2 is a valve 22which is engageable in the forward end portion of the fluid passage l5for controlling same. A suitable packing 23 is provided on the'dome l2for the valve 22.- The valve, 22 is mounted on one end of a stem 24which extends slidably into the drive shaft I. Mounted transversely onthe forward end portion of the stem 24 is a pin 25 which is operable ina longitudinal slot 26 provided therefore in the drive shaft I. Mountedon the pin 25 for sliding movement on the drive shaft l is a groovedcollar. 21. A manually operable'lever or pedal 28v is operativelyconnected to the collar 21 for 22. The chamber 30 also accommodates acoil spring 3| or other resisting medium which yieldingly urges thevalve 22toward closed position. It may be well to here state that theslot 26' in which the pin 25 is operable positively limits themovementof the valve 22 under the influence of therein a centrallylocated expansion chamber 32 which communicates with the fluid chamberH. A piston 33 is operable in the expansion chamber 32. A coil spring 34in. the expansion chamber 32 yieldingly suppo s the piston 33.

The reference numeral 35 (see Fig. 1) designates a driven shaft havingan enlargement or head 36 on its forward end. The head 36 is journaledin a suitable bearing 31. Extending into the head 36 from the forwardend thereof is a spirally threaded socket 38. Also formed longitudinallyin the head 36 is a cylinder 33 which communicates with the socket 33.The socket 33 is for the reception of a spirally threaded shank 40 whichprojects rearwardly from the driven member 6. Projecting rearwardly fromthe shank 40 is a reduced plunger ll which is operable in the cylinder39. A coil spring 42 or other re-' sisting medium in the cylinder 33yieldingly resists rearward movement of the plunger 4| -in moved towardclosed position the circulation of the fluid through the passage I5 isrestricted.

The resistance thus created to the pumps |'I,,

which is transmitted to the gears l3, causes the member 6 to turnwiththe flywheel 2. When the valve 22 is fully closed the fluid can nolonger circulate and in this manner the pumps H are locked. As the gearsl9 are also looked against movement on the gear 4 a direct drive is hadbetween the members 2 and 6. From the foregoing it will be seen that byoperating the valve 22 the speed at which the member 5 will be drivenmay be progressively raised and lowered as desired. The chamber 32permits expansion of the fluid and, in addition, maintains thecirculating system of the transmission substantially full at all times.

With valve 22 in closed position and should the load on the drive shaftincrease sumciently as to stop or retard the "rotation of the drivenshaft overthe speed of rotation of the member 6 which is now locked tothe flywheel, the spirally pitched threads 40 coacting with the spirallypitched threads 38 will bring about movement of the member 6 toward thedrive shaftand unseat the valve 22 and thereby interrupt the directdrive between the fly wheel and the member 6 until the load is againreduced whence the spring 32 acts to restore the member 6 to its initialposition, again seating the valve to bring about direct drive betweenthe fly wheel and the member 6.

It is'believed that the many advantages of a hydraulic transmissionconstructed in accordance with the present invention will be readilyunderstood and although a preferred embodiment of the device is asillustrated and described, it is to be understood that changes in thedetails of construction and in the combination and arrangement of partsmay be resorted to which will fall within the scope of the invention asclaimed.

What is claimed is:

1. A hydraulic transmission comprising a driving member, a driven memberrotatable relative to said driving member, the driven member having afluid chamber therein, a case mounted on the driven member and rotatablein the driving member, said case having a fluid chamber therein andfurther having a passage therein connecting the first and second namedchambers, pumps mounted in the case for circulating the fluid, gearsoperatively connecting said pumps to the driving member for actuationthereby, and a valve slidably mounted in the driving member andengageable in the passage for regulating the circulation of the fluidand. controlling the operation of the pumps.

2. A hydraulic transmission of the character described comprising adriving member, a driven member, said driven member having a fluidchamber therein, a case mounted on the driven member and rotatable inthe driving member, said case including a pair of complemental disks, adome on one of said disks providing a fluid chamber, the disks having acentrally located passage therethrough establishing communicationbetween the chambers for the passage of the fluid, gear pumps mounted inthe case between the disks for circulating the fluid through the passagebetween the chambers, gears operatively connecting the pumps to thedriving memmember further having an expansion chamber thereincommunicating with oneof the first named chambers, and means in theexpansion chamber for yieldingly resisting the entrance of the fluidthereinto.

4. A hydraulic transmission comprising, in

. combination, a drivingmember, a driven member rotatable and slidablein said driving member, said driven member having a fluid circulatingsystem therein, pumps in the driven member for circulating the fluidthrough the system, means operatively'connecting said pumps to thedriving member for actuation thereby, a stationary valve mounted in thedriving member for controlling the circulation of the fluid in thedriven member, and load. controlled means operatively connected to thedriven member for moving same toward or away from the valve forregulating the circulation of the fluid.

. CHARLES L. MCGAVERN,

